Magneto resistive head having symmetric off-track performance profile

Abstract

A magnetoresistive (MR) head using soft adjacent layer (SAL) transverse biasing and having electrical leads with the facing surfaces lying in planes canted with respect to the easy axis of magnetization of the magnetoresistive sensor element for improving the off-track performance of the MR head by making the off-track performance profile more symmetrical, thereby minimizing the difference between the location of its physical center and its magnetic center.

I claim: 
     
       1. A magnetoresistive device for reading position information within each of plural adjacent data tracks of a magnetic recording medium, the magnetoresistive device comprising: a soft magnetic layer;   a nonmagnetic decoupling layer in contact with said soft magnetic layer;   a magnetoresistive layer in contact with said nonmagnetic decoupling layer; said magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   an element operatively associated with said magnetoresistive layer to produce longitudinal bias in said end regions of said magnetoresistive layer; and   conductive leads in a spaced apart relationship with each other; said leads having spaced facing surfaces extending generally parallel to each other and defining an active region therebetween; said soft magnetic layer producing a transverse bias in said active region sufficient to maintain said active region in linear response mode during operation of said magnetoresistive device; said facing surfaces being canted such that a plane passing coplanarly through one of said facing surfaces defines a predetermined acute angle with respect to the easy axis of said magnetoresistive layer effective to ensure symmetrical off-track response to the position information during operation of said device.   
     
     
       2. The magnetoresistive device of claim 1 wherein said predetermined acute angle is within a range of 80° to 65°. 
     
     
       3. The magnetoresistive device of claim 1 wherein said predetermined acute angle is 68°. 
     
     
       4. The magnetoresistive device of claim 1 wherein the element comprises an antiferromagnetic layer in contact with said magnetoresistive layer. 
     
     
       5. The magnetoresistive device of claim 1 wherein the element comprises permanent magnets at opposite sides of said magnetoresistive layer, said nonmagnetic decoupling layer and said soft magnetic layer. 
     
     
       6. The magnetoresistive device of claim 1 further comprising magnetic shields; one of said shields being located in an immediately spaced apart relationship to said conductive leads and being generally parallel to said conductive leads; another of said shields being located in an immediately spaced apart relationship to said soft magnetic layer and being generally parallel to said soft magnetic layer. 
     
     
       7. A magnetoresistive device for reading position information within each of plural adjacent data tracks of a magnetic recording medium, the magnetoresistive device comprising: a soft magnetic layer;   a nonmagnetic decoupling layer in contact with said soft magnetic layer;   a magnetoresistive layer in contact with said nonmagnetic decoupling layer; said magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   an antiferromagnetic layer in contact with said magnetoresistive layer and operatively associated with said magnetoresistive layer to produce longitudinal bias in said end regions of said magnetoresistive layer; and   conductive leads in a spaced apart relationship with each other; said leads having spaced facing surfaces extending generally parallel to each other and defining an active region therebetween; said soft magnetic layer producing a transverse bias in said active region sufficient to maintain said active region in linear response mode during operation of said magnetoresistive device; said facing surfaces being canted such that a plane passing coplanarly through one of said facing surfaces defines a predetermined acute angle with respect to the easy axis of said magnetoresistive layer effective to ensure symmetrical off-track response to the position information during operation of said device.   
     
     
       8. The magnetoresistive device of claim 7 wherein said predetermined acute angle is within a range of 80° to 65°. 
     
     
       9. The magnetoresistive device of claim 7 wherein said predetermined acute angle is 68°. 
     
     
       10. A magnetoresistive device for reading position information within each of plural adjacent data tracks of a magnetic recording medium, the magnetoresistive device comprising: a soft magnetic layer;   a nonmagnetic decoupling layer in contact with said soft magnetic layer;   a magnetoresistive layer in contact with said nonmagnetic decoupling layer; said magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   permanent magnets at opposite sides of a trilayer structure, said trilayer structure being defined by said magnetoresistive layer, said nonmagnetic decoupling layer and said soft magnetic layer; said permanent magnets operatively associated with said magnetoresistive layer to produce longitudinal bias in said end regions of said magnetoresistive layer; and   conductive leads in spaced apart relationship with each other; said leads having spaced facing surfaces extending generally parallel to each other and defining an active region therebetween; said soft magnetic layer producing a transverse bias in said active region sufficient to maintain said active region in linear response mode during operation of said magnetoresistive device; said facing surfaces being canted such that a plane passing coplanarly through one of said facing surfaces defines a predetermined acute angle with respect to the easy axis of said magnetoresistive layer effective to ensure symmetrical off-track response to the position information during operation of said device.   
     
     
       11. The magnetoresistive device of claim 10 wherein said predetermined acute angle is within a range of 80° to 65°. 
     
     
       12. The magnetoresistive device of claim 10 wherein said predetermined acute angle is 68°. 
     
     
       13. A magnetoresistive device for reading position information within each of plural adjacent data tracks of a magnetic recording medium, the magnetoresistive device comprising: a magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   conductive leads in spaced apart relationship with each other and electrically connected to said magnetoresistive layer, said leads having spaced facing surfaces which extend generally parallel to each other and define an active region therebetween, said facing surfaces being canted such that a plane passing coplanarly through one of said facing surfaces defines a predetermined acute angle with respect to said longitudinal axis to ensure symmetrical off-track response to the position information during operation of said device;   an element operatively associated with said magnetoresistive layer to produce longitudinal bias in at least a portion of said magnetoresistive layer;   a soft magnetic layer spaced apart from said magnetoresistive layer for producing transverse bias in at least a portion of said active region; and   a nonmagnetic layer interposed between said magnetoresistive layer and said soft magnetic layer for magnetically decoupling said magnetoresistive layer from said soft magnetic layer.   
     
     
       14. A magnetoresistive read transducer for reading position information within each of plural adjacent data tracks of a magnetic recording medium, said transducer comprising: a magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   conductive leads in spaced apart relationship with each other and electrically connected to said magnetoresistive layer for providing a sense current through said magnetoresistive layer, said leads having spaced apart facing surfaces which extend generally parallel to each other and define an active region therebetween, each of said facing surfaces being canted such that a plane passing coplanarly through one of said facing surfaces defines an acute angle with respect to said longitudinal axis to ensure symmetrical off-track response to the position information during operation of said transducer;   longitudinal biasing means operatively associated with said magnetoresistive layer for maintaining a single domain state in said end regions; and   soft adjacent layer means for providing transverse bias in at least a portion of said active region.   
     
     
       15. A magnetoresistive read transducer for reading position information within each of plural adjacent data tracks of a magnetic recording medium, said transducer comprising: a magnetoresistive layer having a longitudinal axis and having spaced apart end regions thereon and having an easy axis of magnetization substantially parallel to said longitudinal axis;   conductive leads in spaced apart relationship with each other and electrically connected to said magnetoresistive layer for providing a sense current through said magnetoresistive layer, said leads having spaced apart facing edges which extend generally parallel to each other and define an active region therebetween, each of said facing edges being canted such that a line passing coplanarly through one of said facing edges defines an acute angle with respect to said longitudinal axis to ensure symmetrical off-track response to the position information during operation of said transducer;   longitudinal biasing means operatively associated with said magnetoresistive layer for maintaining a single domain state in said end regions; and   soft adjacent layer means for providing transverse bias in at least a portion of said active region.